Omnidirectional antenna system employing plural, spaced, perpendicularly polarized radiators

ABSTRACT

An omnidirectional antenna includes several individual radiators which are arranged on the superficies of a preferably cylindrical body which has a diameter which is relatively great in comparison to the operative wavelength of the antenna. Adjacent individual radiators are polarized perpendicularly to each other and are overlapping in the range of their half power (3db. point). At least two additional individual radiators are provided at each median perpendicular of the plane given by the individual radiators which are arranged on the superficies and on the outer surface of the body and they are polarized perpendicularly relative to the adjacent individual radiators.

United States Patent [72] lnventols KarIKoob Munich; Joachim Hermann, Duerrnhaar, both of, Germany [Zl] Appl. No. 28,461

[22] Filed Apr. 14, i970 [45] Patented July 20, 197 l [73] Assignee Messerschmitt-Bolkow-Blohm Gesellschaft mitbeschrankter Haftung Munich. Germany [32] Priority May 28, 1969 [33] Germany [54] OMNIDIRECTIONAL ANTENNA SYSTEM EMPLOYING PLURAL, SPACED, PERPENDICULARLY POLARIZED RADIATORS 6 Claims, 3 Drawing Figs.

{52] [1.8. CI 343/799, 343/DlG. 3, 343/705, 343/890 [51] lnt.Cl 1101:; 1/28,

HOlq 21/20 [50] Field of Search ..343/DlG. 3, 705, 708, 799, 776, 777, 778, 890, 908

{56] References Cited UNITED STATES PATENTS 2,955,288 10/1960 Palmer 343/890 3,127,609 3/1964 Wentworth 343/708 Primary ExaminerEli Lieberman Att0rneyMcGlew and Toren ABSTRACT: An omnidirectional antenna includes several individual radiators which are arranged on the superficies of a preferably cylindrical body which has a diameter which is relatively great in comparison to the operative wavelength of the antenna. Adjacent individual radiators are polarized perpendicularly to each other and are overlapping in the range of their half power (3db. point). At least two additional individual radiators are provided at each median perpendicular of the plane given by the individual radiators which are arranged on the superficies and on the outer surface of the body and they are polarized perpendicularly relative to the adjacent individual radiators.

PATiNTEnJuLzmsn 3,594,808

INVENTORS Joachim Hermann Karl Koob By W9C TC u vv ATTORNEYS OMNIDIRECIIONAL ANTENNA SYSTEM EMPLOYING PLURAL, SPACED, PERPENDICULARLY POLARIZED RADIATORS SUMMARY OF THE INVENTION This invention relates in general to the construction of an antenna and in particular to a new and useful omnidirectional antenna having several individual radiators arranged on the outer periphery, or surface, of a preferably cylindrical body whose diameter is great relative to the operating wavelength of the antenna.

The present invention deals in particular with an antenna having individual radiators which are polarized perpendicularly to each other and the radiation diagrams of the individual radiators overlap in the range of their half power (3 db.- point). With such an omnidirectional antenna a practically ideal circular radiation pattern is achieved particularly in missiles used in aviation and space navigation. The diameter of the missiles carrying the individual radiators is great relative to the operating wavelength of the antenna. The perpendicular direction of polarization of adjacent individual radiators of this antenna antenna construction described in our copending application Ser. No. 761,798, prevents the electromagnetic waves radiated by adjacent individual radiators from interfering with each other and resulting in weakening or extinction of the radiated energy in certain regions of the radiation characteristic.

The omnidirectional antenna described in the known construction has a very good circular radiation pattern in the plane given by the individual radiators which also has radiation portions in directions including an angle of up to 160 with respect to this plane and corresponding to the vertical angle of aperture of the radiation lobes starting from the individual radiators. Consequently, little energy is radiated into regions which are outside this vertical angle of radiation. For this reason radio communication with an omnidirectional antenna of the described construction in directions extending substantially perpendicularly to the plane given by the in dividual radiators is only possible with considerable expenditure.

It is an object of the present invention to improve the omnidirectional antenna of the type described above in such a way that it permits radio communication in a simple manner in directions forming any angle with the plane given by the individual radiators, that is, the radiation diagram of the antenna comes as close as possible to a spherical pattern. This problem is solved according to the invention by providing at least two additional individual radiators arranged on the median perpendicular of the plane given by the individual radiators arranged on the exterior surface of the body and which are polarized perpendicularly with respect to the adjacent individual radiators. With such an advantageous further development of the omnidirectional antenna, the radiation is also achieved in directions perpendicular to the plane given by the individual radiators which are arranged on the superficies of the body. Since these additional individual radiators are also polarized perpendicularly relative to the adjacent individual radiators, hence relative to the individual radiators arranged by the exterior surfaces of the body, no interferences are possible even between the electromagnetic waves radiated by the additional individual radiators and the individual radiators arranged on the superficies of the body. Due to these additional individual radiators, a substantially spherical pattern is thus obtained as a radiation diagram.

The omnidirectional antenna designed according to the invention can be equipped either with horn-shaped or dipole radiators, adjacent radiators being polarized perpendicularly to each other. And elliptically polarized helical radiators can also be used, adjacent radiators being polarized in opposite directions of rotation.

According to a special embodiment of the invention, the additional individual radiators are elliptically polarized and the individual radiators arranged on the superficies of the body are linearly polarized or vice versa. Thus, with an arrangement in which a strictly linear polarization is employed along with an elliptical polarization composed of two waves polarized linearly perpendicularly to each other, the radiation pattern can be influenced within certain limits.

Accordingly, it is an object of the invention to provide an omnidirectional antenna having several radiators arranged around the superficies of a preferably cylindrical body whose diameter is great relative to the operative wavelength of the antenna and wherein the radiators are polarized perpendicularly to each other and overlapping in the range of their half power (3 db.-point) and further wherein two additional individual radiators are provided on any respective median perpendicular to the plane given by the individual radiators which are arranged on the superficies, the additional radiators being arranged on the outer surface of the body and being polarized perpendicularly relative to the adjacent individual radiators which are on the superficies.

A further object of the invention is to provide an omnidirectional antenna which is simple in design, rugged in construction and economical to manufacture.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated and described preferred embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. I is a front top elevational view of an omnidirectional antenna having horn-shaped radiators constructed in accordance with the invention;

FIG. 2 is a view similar to FIG. 1 of another embodiment of the invention; and

FIG. 3 is a view similar to FIG. 1 of still another embodiment of the invention.

GENERAL DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings in particular, the invention embodied therein in FIG. 1 comprises an omnidirectional antenna which includes a substantially cylindrical body having a cylindrical surface with horn-shaped radiators 2, 3, 4 and 5, arranged therearound at evenly spaced locations. In accordance with the invention, two additional horn-shaped radiators 6 and 7 are arranged in the centers of the end faces of the body 1. The horn-shaped radiators are so arranged and fed that the radiated electromagnetic waves of adjacent hornshaped radiators, for example the radiators 2 and 6, are polarized perpendicularly to each other. The directions of polarization of the individual horn-shaped radiators are indicated in the drawing by the arrows.

In the embodiment of the omnidirectional antenna represented in FIG. 2, there is provided a cylindrical body 1' which carries dipole radiators rather than horn-shaped radiators, the radiators being similarly designated but with an additional prime. The dipole radiators are so aligned with respect to the body 1 that adjacent dipole radiators, for example the radiators 2' and 6' are polarized perpendicularly to each other.

In the embodiment of FIG. 3, there is provided an omnidirectional antenna having a cylindrical body ll" and which includes elliptically polarized helical radiators designated with similar numerals to that of the other embodiments but with a double prime. Adjoining individual radiators are polarized in opposite directions of rotation. Since each elliptically polarized wave can be decomposed into two waves polarized linearly perpendicularly to each other, helical radiators polarized in opposite directions of rotation can be considered as being polarized perpendicularly to each other. For this reason, the electromagnetic waves radiated by the individual radiators 2' and 6', for example, act like perpendicularly polarized waves, even though both individual radiators are polarized in a counterclockwise direction in this case. Each elliptically polarized individual radiator may be fed with such a phase that an orthogonal polarization is obtained in as many directions in space as possible.

Since adjacent individual radiators must be polarized perpendicularly to each other, the total number of individual radiators provided on the antenna support must be an even number. The radiation diagrams of the individual radiators must overlap in the points of the half power (3 db. point) since the spherical characteristic of the entire antenna system formed as a summation diagram is obtained by simple addition of the radiation diagrams of the individual radiators.

What we claim is:

1. An omnidirectional antenna, including a body having several individual radiators arranged on the superficies thereof, said body having a diameter which is great relative to the operative wavelength of the antenna, adjacent individual radiators being polarized perpendicularly to each other and overlapping in the range of their half power (3 db.-point), at

least two additional individual radiators arranged on the median perpendicular of the plane given to the individual radiators which are arranged on the superficies, said two additional radiators being on the outer surface of said body and being polarized perpendicularly relative to the adjacent individual radiators which are located on the superficies of said body.

2. An omnidirectional antenna, according to claim 1, wherein said individual additional radiators are polarized elliptically and said individual radiators on the superficies of said body are polarized linearly.

3. An omnidirectional antenna, according to claim 1, wherein said additional individual radiators are polarized linearly and the individual radiators on the superficies of said body are polarized elliptically.

4. An omnidirectional antenna, according to claim 1, wherein said individual radiators and said additional radiators are horn-shaped.

5. An omnidirectional antenna, according to claim 1, wherein said individual radiators and said additional radiators are dipole.

6. An omnidirectional antenna, according to claim 1, wherein said individual radiators and said additional radiators are elliptically polarized helical radiators. 

1. An omnidirectional antenna, including a body having several individual radiators arranged on the superficies thereof, said body having a diameter which is great relative to the operative wavelength of the antenna, adjacent individual radiators being polarized perpendicularly to each other and overlapping in the range of their half power (3 db.-point), at least two additional individual radiators arranged on the median perpendicular of the plane given to the individual radiators which are arranged on the superficies, said two additional radiators being on the outer surface of said body and being polarized perpendicularly relative to the adjacent individual radiators which are located on the superficies of said body.
 2. An omnidirectional antenna, according to claim 1, wherein said individual additional radiators are polarized elliptically and said individual radiators on the superficies of said body are polarized linearly.
 3. An omnidirectional antenna, according to claim 1, wherein said additional individual radiators are polarized linearly and the individual radiators on the superficies of said body are polarized elliptically.
 4. An omnidirectional antenna, according to claim 1, wherein said individual radiators and said additional radiators are horn-shaped.
 5. An omnidirectional antenna, according to claim 1, wherein said individual radiators and said additional radiators are dipole.
 6. An omnidirectional antenna, according to claim 1, wherein said individual radiators and said additional radiators are elliptically polarized helical radiators. 